The present invention relates to a member for feeding a lubricant. More particularly, this invention relates to a lubricant feeder which is interposed between members rolling or sliding on each other, and is used for lubricating these members. The present invention also relates to a linear apparatus having such a member for feeding a lubricant.
The present application is based on Japanese Patent Application No. Hei. 9-152452, which is incorporated herein by reference.
This kind of lubricant feeder, which comprises a polymer containing a lubricant, is disposed so as to be in contact with a part required to be lubricated, such as, e.g., a linear guide bearing, a ball screw, or an oil seal, and to automatically feed the lubricant to the part.
Examples of this kind of lubricant feeder include the lubricant feeder described in Japanese Utility Model Unexamined Publication No. Hei. 7-4952 (hereinafter referred to as "the first prior art example") and that described in Japanese Patent Unexamined Publication No. Hei. 6-346919 (hereinafter referred to as "the second prior art example").
The first prior art example, which comprises a polymeric member containing a lubricant, is fitted to a ball screw at each end of the nut so as to be slide on the screw groove of the thread shaft and to serve also as a sealing member. The lubricant gradually oozes out of the polymeric member with the lapse of time and is automatically fed to the balls via the screw groove. Thus, the lubricant feeder performs its lubricating function over long periods of time.
The second prior art example, which is a sealing member made of a rubber or synthetic resin containing a lubricant, is used, for example, as side seals to be attached to the slider of a linear guide so that the sealing lip parts thereof are in contact with rolling element rolling grooves formed on the side surfaces of the guide rail. The lubricant gradually oozes out of the rubber or synthetic resin with the lapse of time and is automatically fed to the rolling elements via the rolling element rolling grooves. Thus, the lubricant feeder performs its function over long periods of time.
However, the conventional lubricant feeders have the following problems. The first problem is that when the conventional lubricant feeders are used in food-processing machines for food production, etc., there is a possibility that the lubricant oozing out of the lubricant feeder might contaminate the foods which are being produced. In the conventional lubricant feeders, no care has been taken to use a lubricant harmless to the human body. It is therefore difficult from a safety standpoint to use the prior art lubricant feeders in the field of food-processing machines and the like.
The second problem is as follows. There is a possibility that components of the synthetic resin (or rubber) constituting the lubricant feeder interposed between members sliding on each other might contaminate the food due to friction with these members. In this point also, no care has been taken to use a synthetic resin or rubber harmless to the human body as the material constituting a conventional lubricant feeder. This also makes it difficult to use the prior art lubricant feeders in food-processing machines or the like.